IPhone 4s ringtone synced and I checked it off, but it still won't play?

When someone calls me, my custom ringtone won't go off, even though I check it and it would successfully play when I pressed it. How can I solve this problem?

Did you go into contacts and make that his ringtone?

If you did, the other answer is that the ios you have does not have to option to play ringtones that are imported.